freebsd kernel with SKQ
8bff5fd956
the old encodings for the lower 16 and 32 bits and only using the higher 32 bits for unusually large major and minor numbers. This change breaks compatibility with the previous encoding (which was only used in -current). Fix truncation to (essentially) 16-bit dev_t in newnfs v3. Any encoding of device numbers gives an ABI, so it can't be changed without translations for compatibility. Extra bits give the much larger complication that the translations need to compress into fewer bits. Fortunately, more than 32 bits are rarely needed, so compression is rarely needed except for 16-bit linux dev_t where it was always needed but never done. The previous encoding moved the major number into the top 32 bits. Almost no translation code handled this, so the major number was blindly truncated away in most 32-bit encodings. E.g., for ffs, mknod(8) with major = 1 and minor = 2 gave dev_t = 0x10000002; ffs cannot represent this and blindly truncated it to 2. But if this mknod was run on any released version of FreeBSD, it gives dev_t = 0x102. ffs can represent this, but in the previous encoding it was not decoded, giving major = 0, minor = 0x102. The presence of bugs was most obvious for exporting dev_t's from an old system to -current, since bugs in newnfs augment them. I fixed oldnfs to support 32-bit dev_t in 1996 (r16634), but this regressed to 16-bit dev_t in newnfs, first to the old 16-bit encoding and then further in -current. E.g., old ad0 with major = 234, minor = 0x10002 had the correct (major, minor) number on the wire, but newnfs truncated this to (234, 2) and then the previous encoding shifted the major number into oblivion as seen by ffs or old applications. I first tried to fix this by translating on every ABI/API boundary, but there are too many boundaries and too many sloppy translations by blind truncation. So use the old encoding for the low 32 bits so that sloppy translations work no worse than before provided the high 32 bits are not set. Add some error checking for when bits are lost. Keep not doing any error checking for translations for almost everything in compat/linux. compat/freebsd32/freebsd32_misc.c: Optionally check for losing bits after possibly-truncating assignments as before. compat/linux/linux_stats.c: Depend on the representation being compatible with Linux's (or just with itself for local use) and spell some of the translations as assignments in a macro that hides the details. fs/nfsclient/nfs_clcomsubs.c: Essentially the same fix as in 1996, except there is now no possible truncation in makedev() itself. Also fix nearby style bugs. kern/vfs_syscalls.c: As for freebsd32. Also update the sysctl description to include file numbers, and change it to describe device ids as device numbers. sys/types.h: Use inline functions (wrapped by macros) since the expressions are now a bit too complicated for plain macros. Describe the encoding and some of the reasons for it. 16-bit compatibility didn't leave many reasonable choices for the 32-bit encoding, and 32-bit compatibility doesn't leave many reasonable choices for the 64-bit encoding. My choice is to put the 8 new minor bits in the low 8 bits of the top 32 bits. This minimizes discontiguities. Reviewed by: kib (except for rewrite of the comment in linux_stats.c) |
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| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| stand | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| Makefile.sys.inc | ||
| ObsoleteFiles.inc | ||
| README | ||
| README.md | ||
| UPDATING | ||
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.
Source Roadmap:
bin System/user commands.
cddl Various commands and libraries under the Common Development
and Distribution License.
contrib Packages contributed by 3rd parties.
crypto Cryptography stuff (see crypto/README).
etc Template files for /etc.
gnu Various commands and libraries under the GNU Public License.
Please see gnu/COPYING* for more information.
include System include files.
kerberos5 Kerberos5 (Heimdal) package.
lib System libraries.
libexec System daemons.
release Release building Makefile & associated tools.
rescue Build system for statically linked /rescue utilities.
sbin System commands.
secure Cryptographic libraries and commands.
share Shared resources.
stand Boot loader sources.
sys Kernel sources.
sys/<arch>/conf Kernel configuration file
tests Regression tests which can be run by Kyua. See tests/README
for additional information.
tools Utilities for regression testing and miscellaneous tasks.
usr.bin User commands.
usr.sbin System administration commands.
For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see:
https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/current-stable.html